Spring supporting strip having a top seating portion spaced above a bottom reinforcing portion



H. c. FLINT 2,629,431 SPRING SUPPORTING STRIP HAVING A TOP SEATING PORTION Feb. 24, 1953 SPACED ABOVE A BOTTOM REINFORCING PORTION Filed March 29, 1950 3 Sheets-Sheet l V INVENTOR.

Feb. 24, 1953 H. c. FLINT 2,629,431

SPRING SUPPORTING STRIP HAVING A TOP SEATING PORTION SPACED ABOVE A BOTTOM REINFORCING PORTION Filed March 29, 1950 5 Sheets-Sheet 2 INVENTOR.

Hal 407 CT 712/12:

Feb. 24, 1953 H. c. FLINT 2,629,431

SPRING SUPPORTING STRIP HAVING A TOP SEATING PORTION SPACED ABOVE A BOTTOM REINFORCING PORTION Filed March 29, 1950 3 Sheets-Sheet 5 Z5 INVENTOR.

Patented Feb. 24, 1953 SPRING SUPPORTING'STRIP HAVING A TOP SEATING PORTION SPACED ABOVE A BOT- TOM REINFORCING PORTION Hyland C. Flint, Birmingham, Mich., assignor to American Metal Products Company, Detroit, Mich, a corporation of Michigan Application March 29, 1950, Serial N 0. 152,727

13 Claims.

This invention relates to spring construction and in particular to those embodying sinuous or zigzaz springs of the type disclosed and claimed in Kaden Reissue Patent No. 21,263.

The present invention provides a zigzag spring unit having at least two vertically spaced web portions, the upper of which defines the resilient load supporting surface. The webs are resiliently connected together and jointly connected in a resilient manner to the frame. During the application of seat loads below a predetermined value, the lower web serves merely as a resilient reaction member to support the upper web. However, when the loads exceed this value, the upper web is deflected into engagement with the lower so that both directly receive and resiliently support the seat loads. This construction therefore automatically furnishes an additional load receiving web to directly assist in the support of loads above a predetermined magnitude and increase the stiffness of the spring unit or its rate of deflection relative to the load. This concept virtually eliminates the danger of non-resilient bottoming of the seat under abnormal loads. It therefore serves as an automatic safety or overload device that enables the engineer to concentrate upon the characteristics desired in the normal load range and design the spring units to more efficiently supply them.

As a further advantage, the structure of the invention adapts itself to spacing above the floor without sacrifice in resiliency or increase in the complexity of manufacture. This provides toe or foot room beneath the seat and also space for underseat air circulation.

The invention is illustrated in the accompanying drawings in which:

Figure 1 is a plan view of a tractor seat embodying spring units constructed in accordance with the principles of the invention;

Figs. 2 and 3 are sections taken, respectively, on lines 2-2 and 33 of Fig. 1;

Fig, 4 is a detail view in perspective of a suitable clip for interconnecting the spring comprising the spring unit of this invention;

Figs. 5, 6 and '7 are views taken, respectively, on lines 5-5, 6- -6 and 'i'! of Figs. 2 and 3;

Fig. 8 is a view similar to that of Fig. '7 showing a modified form of deadening pad;

Fig. 9 is a plan view of a seat, such as an automobile seat, embodying modified forms of spring units constructed in accordance with the principles of the invention;

Fig. 10 is a cross-section taken on line ill-l0 of Fig. 9; and

Figs. 11 and 12 are sections similar to that of Fig. 10 illustrating modified forms of spring units constructed in accordance with the invention.

The zigzag spring unit of this invention is illustrated first in a novel tractor seat construction shown in Figs. 1 and 2 of the drawing. The seat has a frame l of suitable construction that may be mounted upon the platform of the tractor. Preferably, the frame comprises an endless rectangular tube that has transversely spaced longitudinally extending tubes or support bars 3 welded thereto at intermediate transverse portions of the front and rear cross-members 5 and 1' respectively of frame I.

The zigzag spring units which form the resilient seating surface extend transversely of the frame, and those springs which form the front edge and the rear edge of the resilient surface may be constructed in accordance with the prin ciples of the prior art. Thus the front spring 9 and the rear spring II, which may, for the sake of illustration, be assumed to be identical, are

formed from continuous or zigzag spring wire of the type disclosed and claimed in the Kaden Reissue Patent No. 21,263. Each consists of a longitudinal series of oppositely opening U- shaped turns, or, as they are commonly referred to, adjacent oppositely disposed loops comprising straight sections joined by arcuate sections.

Both the front and rear springs Q and l have an intermediate web portion I? and end portions that are bent beneath the web portion. The end portions comprise sections is that are preferably bent at substantially right angles to the web portion 11. In the embodiment shown in the draw-' ings, since the web portion is crowned slightly, the end portions are slanted inwardly slightly from the vertical. The length of the end portion [9 is determined by the desired height above the frame I of the seating surface provided by the web 11, and, in the illustrations, consists of three turns or loops of wire. The transverse length of the web ll on each of the front and rear springs, while less than that of the remaining zigzag units to be presently described, is substantially greater than the transverse spacing of the longitudinal support bars 3. Hence, the end portions of the front and rear springs include sections 2! that are bent inwardly from the lower end of the substantially upright section iii. The extremities of the sections 2! and thus also the extremities of the springs 9 and ii are secured to the support bars 3 by suitable means. As illustrated in Figs. 2 and 5, this means may comprise stampings 23 that are formed or contoured to fit the surface of the bars 3, and which are welded or otherwise fixedly secured thereto. Each stamping 23 has dimples 25 pressed therein which are apertured at 21 so that the straight portion at the extremity of the springs may he slipped through the aperture beneath the dimple 25 and confined against the vertical movement between the under surface of the dimple 25 and the upper surface of the support bar 3. Sidewise movement of each of the springs 9 and H at the ends thereof is prevented in one direction by abutment of the end of the straight portion in the dimple 25 with the end of the dimple 25 and in the opposite direction by an upright ear or nib 29 struck from the stamping 23 which engages the arcuate loop or bend adjacent to the end of the spring. Downward pivotal movements of the end section 2| of the front and rear springs relative to the support bar 3 is prevented by a landing or flange 3| which is formed in the stamping 23 and extends upwardly in the direction of the section 2| and which is engaged by the straight section adjacent to the straight section confined in the dimple 25. As may be noted from Fig. 2, the last loop of the end of section 2| of the front and rear springs, which are connected to the stamping 23, is bent slightly relative to the remainder of the section 2|. As will become self-apparent hereinafter, this is principally to account for the difference in slopes between the end section 2| and the corresponding end section on the intermediate zigzag spring unit and enable the stamping 23 to be readily manufactured and employed to attach all of the zigzag springs to the support bar 3.

The zigzag spring units 33 intermediate the front and rear springs 9 and N that have just been described, are constructed in accordance with the principles of this invention and carry the major share of the seat load. Each of the units 33 includes a spring 35 that is similar in shape to the front and rear springs 9 and Thus each has a web portion 31 and end portions bent beneath the web each of which comprise a substantially vertical section 39 corresponding to section I9 and an inclined section 4| bent inwardly from the vertical section 39 in a manner similar to the formation of the section 2|. The lower extremities of each section 4| are attached to the support bar 3 by the stamping 23 in the same manner as has been already described for the front and rear springs. However, in addition to the spring 35, each of the spring units 33 has a second zigzag spring 43 that provides a web 45 which is spaced vertically below the web 3'! and which may be regarded as lying substantially entirely in the area of projection of the upper web 31, i. e., the upper and lower webs 31 and d lie in a vertical row or in the region bounded by two planes, each tangent to correspondin outermost curves of the respective loops of one of the webs. The web 45 of the spring 43 is preferably arched or crowned upwardly a slight amount as illustrated, and the endmost loops 4'! of these springs are bent upwardly from the web so that they are parallel to the section 4| of the spring to which they are rigidly attached by suitable means.

Preferably and conveniently, each end loop 41 of the spring 43 may be arranged to overlie similar loops in the section 4| so that the two loops may be clamped together by means of a U-shaped clip 49 such as shown in detail in Fig. 4. The clip 49 is formed from sheet metal into U-shape in plan and cross-section and has a thickness equivalent to that of the two loops combined and fits around the outside of the loops. The crosssection includes ears or arms 5| that may be bent around the inside of the straight portions of the loops to tightly clamp the straight portions together and against the clip. It may be seen that the intermediate spring units 33 might be regarded as polygons, formed of zigzag springs, having a side 37 which is adapted to provide a resilient surface and a base :5 which has depending legs 4| by means of which the polygon is mounted on a frame.

A sound deadening buffer pad 53 of suitable material, such as thick fibre, may be attached by hog rings 55 to a central portion of the web 45 of the lower spring 43. As indicated in Fig. '7, there may be a common pad 53 for all of the spring 43, or as indicated in Fig. 8, a separate pad 53' may be provided for each of the zigzag spring units 33.

The usual border wire 6 i may be placed around the edges of the webs 3i and attached thereto by clips 63, the edges of the webs of the front and rear springs 9 and being attached to support wires by clips 83, the wires 65 being, in turn, secured by suitable clips to the border wire 6|.

As already indicated, the major share of the seat load is taken by the zigzag spring units 33. This load is applied to the web 37 of each unit and is transmitted through the vertical end portions 39 to the end portions 4| that are connected to the support bar 3. The load applied by the sections 39 to the sections 4| causes the latter to bend downwardly on lands 3| thus imparting some resiliency to the spring units. Downward bending of the sections 4| tends to increase, of course, the distance between the point of attachment of the ends 4'! of the spring 43 to the sec tion 4|. Due to the rigid connection 43, this extension or expansion is resisted by the spring 33, which tends to flatten as the load increases. When the load on the web 31 reaches a predetermined value, the web 3'! will have been deflected downwardly to the point where it contacts the web 45 through the medium of the pad 53. At this point, the springs 43 and 35 both directly take the load, and the tendency of the web 45 to downward deflection causes an inward pull on the ends 4'! which is in opposition to the outward pull on these ends caused by deflection of the web 37. Thus there is a substantial stiffening of the unit 33 at this point so that excessive loads on the seat can be withstood in a resilient manner and without bottoming of the springs on the frame or platform.

Figs. 9 to 12 show the use of modified forms of the zigzag spring units of this invention in a conventional automobile seat construction. The seat of Fig. 9 has a frame 7! that is formed of endless tubular stock and includes the front supporting bar 13 and a rear supporting bar 75 joined by side supporting bars IT. The zigzag spring units extend longitudinally of the frame and thus have suitable portions by means of which they are attached at one end to the front bar 13 and at the other end to the rear bar 15. The front and rear edges of the webs of the zigzag spring units, as well as the side edges of the border units, may be attached in conventional manner by clips 19 to a border wire 8|.

Several modified forms of units for use in the seat of Fig. 9 are shown in Figs. 10-12. The zigzag spring unit 83 of Fig. 10 consists of vertically spaced zigzag spring elements 85 and 81. The

upper spring 85 has a web 89 and end portions 9| and 93 bent inwardly beneath the front and rear edges respectively of the web 89. The lower spring 81 has an arcuate web 95, and, the last loops on the end portions 9i and 93 of the upper spring are bent parallel to the web portion 95 and secured thereto by means of clips 49 in a manner already described in connection with Fig. 4. The web 95 of the lower spring 8'! is extended forwardly and rearwardly of the points in connection with the upper springs, and, at the forward end, a portion 91 of the spring is bent beneath the web and secured by clip 99 to the front supporting bar 73. In the embodiment of Fig. 10, the rear supporting bar i5 is jogged or elevated above the front supporting bar by means of uprights IEJI formed in the frame. The rear bar I5 is then spaced above the fioor of an automobile and thus provides toe room for occupants of the rear seat. In order to obtain the desired resiliency, while at the same time obtaining the toe room, the web 95 of the lower spring 8! is extended downwardly from its point of connection with the end portion 93 and then at point I93 is bent upwardly in a section I95 that is securred by means of a suitable clip iii? to the rear supporting bar 15.

It will be observed that the spring unit 83 is a modification of the spring unit 33, previously described, in that the end portions on the lower spring 8'! are connected to the frame, and the upper sprin is supported on the lower spring. The seating load applied to the upper web 85 is therefore resisted by the end ortions HI and 93 of the upper spring as well as by the entire lower spring 87. After a predetermined deflection of the upper web 85, it will contact the lower web 95 through the medium of a pad 53 so that at this point the two webs 89 and 95 will act in series to resist the load and prevent solid bottoming of the spring.

Fig. 11 illustrates another modified form of zigzag spring unit II I constructed in accordance with the principles of this invention which is essentially the same as the unit 93 already described. Thus, it comprises a zigzag spring II3 having a web H5 and end portions at the front and rear thereof which are secured at their lower extremities to the front and rear supporting bars I3 and 75 of the frame. The front supporting section for the web H5 consists of a portion Ill that is bent inwardly beneath the front end of the web H5 and then outwardly to form section II9 that is connected by a suitable clip, such as stamping 29 to the front supporting bar 13. The end portion of the spring H3 for supporting the rear of the web I I5 comprises a section I2I which is bent inwardly beneath the web and then outwardly in a section i23 which is joined by clip 29 or the like to the rear supporting bar 15. A second zigzag spring I25 is connected to the end portion of the upper spring H3 and provides a web I21 that is spaced vertically beneath the upper web H5. The endmost loops of the lower spring I25 are rigidly and non-pivotally connected to the front section l I 9 and the rear section I23 of the spring l I3 by means of clips 69 or the like. A pad 53 may be applied to the upper surface of theweb I2? to engage the web I I5 and prevent noisy contact between the springs. It is evident that the spring unit HI functions in the same manner as the spring unit 33 already described.

The zigzag spring unit I91 of Fig. 12 represents a combination of the units 83 and III shown in Figs. 10 and 11 wherein an upper zigzag spring at Q and a lower zigzag spring each has one end portion secured to a supporting bar, the upper spring being illustrated as attached to rear bar I5 while the lower spring is shown attached to front bar I3. In the embodiment of Fig. 12, both the front and rear supporting bars 13 and 15 are shown elevated above the side supporting bar 11 so as to provide toe room or space beneath the seat construction. The upper spring I33 has a web I35 and a front end portion comprising a section I31 that is bent inwardly from the end of the web I35 and connected by means of a vertical spacer loop I39 to a section MI of the upper sprin that is bent outwardly and forwardly with respect to the web I35 and secured by means of a clip 23 or the like to the front supporting bar I3. At the rear end of the web I35, there is merely a section I43 that is bent beneath the web. The lower spring I45 has a web I4! which is connected by means of a clip 49 to the end of the section I43 whereby it serves to support the upper spring I33. The web I41 extends rearwardly beyond its point of connection with the end section I93 and is secured by means of a suitable clip to the rear support bar I5. The front of the web Ml, however, is connected to the front end portion of the spring I33. This is conveniently accomplished by bending the last forward loop of the spring I45 so that it is parallel to the spacer loop I39 and rigidly connecting it thereto by means of a clip 49. A buffer pad 53 may be secured to the web I4! as before.

As in the other spring units, the lower spring I45 of the spring unit I3I serves to assist in the resilient support of the load upon the upper web I35 and when that web has been deflected a sufficient amount, it contacts the lower web I4? so that both supply a stiffened but yieldable support to the seat load.

It is evident from the modifications shown and described herein that the invention is susceptible of variations, hence, is not intended to limit it to the specific structures shown and described by Lvay of illustration of the rinciples of the invenion.

What is claimed is:

1. A zigzag spring unit comprising an upper zigzag sprin having a web portion and end portions bent beneath the web portion, a lower zigzag spring beneath the upper having a web portion lying substantially entirely in the area of projection of the upper web, means rigidly connecting the lower spring to the end portions of the upper so that the webs are spaced, and spring portions for attachment to a frame beneath the lower web integral with at least one of the springs.

2. A zigzag spring unit comprising an upper zigzag spring having a web portion and ends bent beneath the web portion, a lower zigzag spring beneath the upper having a web portion lying substantially entirely in the area of projection of the upper web, and means rigidly connecting the ends of the lower spring to intermediate points on the ends of the upper spring whereby the portions of the ends beneath the second web may serve as means to attach the unit to a frame.

3. A zigzag spring unit comprising an upper zigzag spring having a web portion and ends bent beneath the web portion, a lower zigzag spring beneath the upper having a web portion lying substantially entirely in the area of projection of the upper web and ends extending below the second web portion, and means rigidly interconnecting the second web to the extremities of the upper spring so that the ends of the second spring extend beneath the webs and serve. as means to attach the unit. tov a frame.

4. A zigzag spring unit comprising an upper zigzag spring having a web portion and end portions bent beneath the web portion, and a lower zigzag spring beneath. the. upper having a web portion lying substantially entirely in the area of projection of the upper web, means ri idly connecting the lower spring to the end portions of the upper so that the webs are spaced, one of said end portions and a. portion of said lower spring extending beneath the lower web for attaching the unit to a frame.

5. A zigzag spring unit comprising an upper zigzag spring having a web portion and end portions bent beneath the web portion, and a lower zigzag spring beneath the upper having a web portion lying substantially entirely in the area of projection of the upper web, means rigidly connecting the lower spring to the end portions of the upper so that the webs are spaced, and spring portions for attachment to a frame beneath the lower web integral with at least one of the springs, one of the spring portions being bent outwardly and upwardly.

6. A zigzag spring unit comprising a first zigzag spring having a web defining a resilient load supporting surface, a second zigzag spring having a web spaced below said web and lying subs'tantially in the area of projection thereof, zigzag spring elements non-pivotally interconnecting the webs to yieldably space them apart and transmit load from the first or upper web to the second or lower web, said spacing being such that the application of loads exceeding a pre- 1 determined maximum on the upper web overcomes the resistance of said elements to allow said web to deflect into engagement with the lower web, and zigzag spring elements non-pivotally interconnected to the webs and extending therebeneath to serve as legs or supports for attachment to a frame.

7. The invention as claimed in claim 6 wherein the zigzag spring elements are integral with the springs.

8. In a spring construction, the combination of a frame having longitudinal members and transverse members, one of the transverse members being spaced above the plane of the longitudinal members, a plurality of substantially parallel, longitudinally extending zigzag spring units secured to the transverse members, said units each including upper and lower vertically spaced longitudinally extending webs and resilient elements interconnecting and spacing the webs and capable of permitting the upper web to contact the lower when loads exceeding a cer tain value are applied to the upper web.

9. In a spring construction, the combination of a frame having longitudinal members and transverse members, a plurality of substantially parallel transversely extending spring units secured to the longitudinal members, said units including upper and lower vertically spaced transversely extending webs and resilient elements interconnecting and spacing the webs and capable of permitting the upper web to con tact the lower when loads exceeding a certain value are applied to the upper web.

10. In a spring construction, the combination of a frame including spaced spring supporting members, a. plurality of substantially parallel spaced zigzag spring units, each of said units comprising an upper zigzag spring having a web portion and end portions bent beneath the web portion, each of said units including a lower zigzag spring beneath the upper having a web portion lying substantially entirely in the area of projection of the upper web, each of said units including means rigidly connecting the lower spring to the end portions of the upper so that the webs are spaced, and spring portions beneath the lower web integral with at least one of the webs, and means rigidly securing the extremities of the spring portions to the supporting members.

11. In a spring construction, the combination of a frame including spaced spring supporting members, one of the members being higher than the other with respect to the plane of the frame, a plurality of substantially parallel spaced zigzag spring units, each of said units comprisin an upper zigzag spring having a Web portion and end portions bent beneath the web portion, a lower zigzag spring beneath the upper having a web portion lying substantially entirely in the area of projection of the upper web, means rigidly connecting the lower spring to the end portions of the upper so that the webs are spaced, and spring portions beneath the lower web integral with at least one of the webs, one of the spring portions extending downwardly and outwardly from the lower web and then being bent upwardly to terminate adjacent the higher of the sup-porting members, and means rigidly securing the extremities of the spring portions to the supporting members.

12. In a spring construction, the combination of a first sinuous spring element, a second sinuous spring element spaced below a central portion of the first, each of said elements comprising adjacent oppositely opening U-shaped turns of spring wire, end portions of the first element bent beneath the central portion of the first element, U-shaped turns of the end portions engaging and congruent with at least certain U- shaped turns on the second spring, U-shaped clips extending around the engaging pairs of turns having arms bent around and clamped to the legs of the turns to rigidly and non-pivotally interconnect the elements, and resilient means connected to the elements for mounting them on a frame.

13, A zigzag spring unit comprising a closed polygon formed of zigzag spring wire and having a side adapted to provide a resilient cushion surface, the opposite side of said polygon constitutin a base and having depending legs of zigzag spring wire extending away from the side forming the resilient surface and being adapted for mounting on a frame.

I-IYLAND C. FLINT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 282,746 Mengel Aug. '7, 1883 2,526,184 Matthaei Oct. 17, 1950 2,526,250 Matthaei Oct. 17, 1950 

